Stereotype printing plate



Jan. 1934. M. w. BRUESHABER 4 ,4

STEREOTYFE PRINT ING PLATE Filed March 13 1931 3 Sheets-Sheet l V HHHHHHHHHHHJEHHHHHHHHHHHHHHHHHHHHHHHEE HEHHHHHHHHHHHHHHHEHHHHHHHEHHHHHHHHHHEH HHHHEHHHHHHHHEHHHEHHHHHHHHHHHHHHEHHEH HHHHHHHHHHHHHH[HHHHHHHHHHHHH EHHHEHlEH HHEHHHHHEHHHEHHHHHHHHHHHHHHH HHHHHHHHH lili-.." HEHHEEHHHHHHEE[HEHHHHHHHEHHHEEHHHHHHHH HEHHHHHHHEHHHEHHHHHHHHHHEHHHHEHHHEHHHH HHHHHHHHHHHHHEHHEEEHHHHHHHHHEHHHHHHHHH HEHHHHHHEEHHHEHHHEHHHHHHHHHHHEHHHHHHHH HEHHHHHHHHHHE HHHHHJHHHHHHHHHHHHHHHHHH HHEHEHHJHHHHH HHIIHHHHHHHHHHHHHHHHHHHHHH EE%EHHHEEHHH HJHEHHEEHHHEHHHHHHHHHHHH HH mua:::

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STEREOTYPE PRI NT I NG PLATE Filed March 13, 1931 :s Sheets-Sheet '2 4- M. w. BRUESHABER STEREOTYPE PRINTING PLATE Filed March 13, 1931 3 Sheets-Sheet 3 l atented `fan. 9, 1934 A mms" i Martin Brueshaberg. Chicago, Illaassignor to Goss'Printing Press, Company, Chicago, Ill., a

corporation of* Illinois Application March 1 3,- 193 1. 'sr a1 no."522,314

' momma: (erina-sist The present 'invention relates to fa novel 'and improved stereotype printing plate, and, more particularly to such a plate adapted to be'cast at an extremely fast rate. I y

,5 Objects and advantages of the invention will be set forth inpart hereinafter' and in part will be obvious herefrom, or may be learned by practice with the invention, the samebeing realized and attained by means of the instrumentalities 10? and combin'ations pointed out in the appended claims. I f

The invention consists in the novel parts, constructions, arrangements, combinatio ns and imprcvements herein shown anddescribed. 5 V

; The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention. ,v 4 c Of'the drawings: s Figure 1 is a development of the inner surface` of a stereotype printing plate in accordance with the present invention, with the showing of the slo'ping sides of the ribs omitted. r v s Figure 2 is a horizontal cross section taken 'through a median portion of the stereotype casting mechanism and 'showing the stereotypeplate. of the present invention and the core of the mold in which it was cast. V V A Figure 3 is a cross-sectionof the plate taken on the line 3-3 of Figure land showingthe plate, after it has been shaved `to truethe inner faces of'the ribs. Figure 4 isa longitudinal section taken on the line 4-4 of Figure 1 and' showing thelongitue dinal ribs formed on the inner surface of 'the plate.- a t The increased speed of casting of the modern stereotype' casting machine has been accom 40 pli'shed'in part throughfa reduction in, the amount 'of metal contained in the cast p1ates, ,thereby reducing the time required for cooling of, the' plates, as well as reducing the time required for pouring. This reduction in the amount of metal r contained in the plate, however, has necessitated making the plates thinner and `consequently much weaker and less able to stand the high pressures to which the plate is subjected during the printing operation. The lack of strength of the plate is particularly apparent with plates 'Which contain a large amount of open matter, such as display advertisements composedlargely of nonprinting areas. The parts of the plate whichdo not print are, of course, thinner than the printing areas of the plate and these thinner portions of" the plate'readily ,bend under. printing pressures. r I. V The`present'invention has'for its object the provision of-anunus`ua11y strong' and rigid,.yet thin curved stereotypeprinting plate which can. 69` be cast'byautomatic casting machinery operating 'at high speeds, A further object of the invention is the provision of a stereotype plate having an unusual degree of strength which can be finished in the usual stereotype plate finishing machines. Still another object of the invention is the provision of a curved stereotype plate. which is not 'subject to the excessive warping which ordinarilyoccurs in the cooling' of; the usualtype of thin plates when castata high rate. 7 9.

Intaccordance with the present invention, the curved stereotype plates illustrative of the invention areof substantially, the same thickness as the plates nowcast at a high speed, and ,are

provided with additional Strengthening means on the rear face of the plates which cooperate to prevent warpingof the plates during the rapid cooling. The Strengthening means also give 'add-,

ed strength tothe. plates over all its surface but particularly at those points 'where large open SQ areas occur on the face of the plate, and where the plate is very thin,, I r

, Referring now in detail to the accompanying drawings showing the present preferred and illustrative einbodimentof the invention, 'the stereotype plate comprises a substantially semi-cylindrical member provided witha printing face 10, tobe inked and printed in the usual manner.

As is' usual, the printing'face comprises raised portions 11 which conform in shapeto, and are distributed over the outer surface of the plate,

- in accordance with the impression to be produced thereby, The open or low portions 12 of the printing 'face correspond to the white or unprinted portions of the impression to be produced. v

On the reverse` or inner surface of the stereotype plate are provided the usual circumferential ribs 14 which support the plate on the sur face of a printing cylinder during' theprinting operation. These circumferential ribs are'pref- 0` erably relatively low in height and are provided with divergent sides 15, Which thicken the rib near the surface of the plate. These ribs 14, are preferably substantially uniformly spaced, relatively close together and extend from a .point closely adjacent to one of the side edges 16 of the plate to a point similarly spaced from the other side edge.

Other circumferential ribs ,17, Which are of much lower height maybe provided in any desired number and are positioned between pairs or other groups of ribs 14, as desired. These ribs serve to strengthen the plate and are not subjected to shaving during the finishing of the plate after casting.

In accordance with the present invention, a series of longitudinally extending ribs `18 are provided which intersect the circumferential ribs and greatly strengthen the plate, permitting the. plate to be locked up much more tightly and enabling the press to be run at higher speeds. These ribs also give added rigidity and strength to the plate even at those points where the printing face has no raised or printing portions. These longitudinal ribs in addition-to preventing mak ing the plate more rigid during printing render it less susceptible to warping during the extremely rapid cooling of the plate. As embodied, the longitudinal ribs 18 are preferably uniformly spaced, extend axially of the cylinder, from one end of the plate to the other, and are of gradually increasing width from the central portion of the* plate to its side edges. .V

As clearlyshown in Figure 1, the inner or rear surface of the plate is provided with a plurality of 'relatively small recesses 20 of substantially uniform size and shape, each bounded on all its sides by the longitudinal and circumferential ribs 18 and 14. V

To enable the plate to be shaved in the usual plate-finishing machines and for distributing the cutting load on the shaving knife thereof, the longitudinal ribs 18 are preferably inclined at a very small angle to the axis of the curved plate. The usual shaving knife is set axially'of the cylinder and this knife cuts a longitudinal rib 18, engaging the rib over only a very small area at any one time. Preferably, andas embodied, the angle is such that the cutting of one longitudinal rib 18 is completed prior to the beginning of the cutting of the next rib.

r Figure 2 of the drawings illustrates a core of a typical stereotype plate casting machine, adapted to cast the'plates of the' present invention. As embodied, the core 22 is water cooled to hasten the cooling of the molten metal after it is run into the mold, thereby reducing the time elapsi'ng' between pouring. of the metal and' the opening of the mold. The core, on its Convex face', is'xpro vided with grooves which correspond in shape to the desired shape of the ribs on the plate before shaving. V p i f The circurnf erential ribs'- 1f4'. are formed by circumferential grooves of the` usual form', while' the longitudinal ribs 18 are formed byl'ongitudi nal grooves 23 in the core. At the front or 'central portion ofthe* core, the sides of the groove'sare slightly converging. The' sides of'the other grooves also convergeat the sides of a the* core and plate, those at the side' edge'sof the' 'plate being the most convergent. Each groove preferably has itsside 25 which is nearest' the central portion of the plate extending'along a rearward ly and outwardly directed line sothat" the plate can be easily removed from the core, and` the longitudinal ribs 18' at the sides of the plate do not lock with the core,

The depth of the core grooves is slightly in ,excess of that required' for the finished plate, and 'during the finishing of the' plate, the shaving knife reduces' the ribs 14: and 18 to a uniform: height so that the inner surface of the' plate is on a substantially true cylinder. 5 V

It will be understood that the' foregoin'g general description and the following detailed' de scription as well are exemplary and explanatory of the invention but are not restricted thereon.

What I claim is:--

1. A curved stereotype plate having on its inner surface a plurality of substantially circumferential ribs and a plurality of longitudinal ribs.

'2. A curved stereotype plate having on its inner surface a plurality of substantially circumferential ribs and a plurality of longitudinal ribs, said ribs being substantially uniformly spaced with the circumferential ribs intersecting the longitudinal ribs.

3. A curved stereotype plate having on its inner surface a` plurality of substantially circumferential ribsand a plurality of longitudinal ribs, said ribs being substantially uniformly spaced and dividing the inner surface of the plate into a plurality of recessed parallelograms.

4. A curved stereotype plate having on its inner surface a plurality of substantially circumferential'ribs anda plurality of longitudinally. extending ribs, said longitudinal ribs extending at a very slight angle to the axis of the plate.

5. A curved stereotype plate' having on its inner surface a plurality of longitudinally extending ribs which are inclined at a very slight angle relative to the cutting edge of the knife with which the plates are finished, and a plurality of substantially circumferential ribs intersecting the longitudinalribs. r

6. A thin curved stereotype plate having on its inner 'surface two series of ribs, the ribs of one series extending at right angles to those of the other series and extending substantially from one edge of the plate to the other.

7'. A thin curved stereotype plate having on its inner surface two series of ribs, the ribs of one series extending at right angles to those of the other series and intersecting therewith and extending substantially from one" edge of the plate uu to the other. v

8 A thin curved stereotype plate' having on its inner surface two series of ribs, the ribs of one series extending at substantially right angles to those of the otherseries, the ribs of each series 120 being substantially uniformly spaced and extending substantially from* one edge' of the plate to the other. V

9. A thin curved stereotype' plate having on its`- inner' surface two' series of ribs, the ribs of one 125 series extending at substantially right angles to those of the other series', the ribs of one series being substantially uniformly spaced, the' ribs of the' other series' being of gradually increasing width away from the' central-portion' of the plate. 180

1C). A curved stereotype plate having on its inj-' ner surface a plurality of circumferential ribs and: a plurality of long tudinal-'iy extending ribs, the longitudinal 'ribs being formed with sides whichconverge towards the axis' of crvatur'e of the plate, the sides nearest to" the central' por'- ti'orr o'f the plate convergirig towards points bey`on"dtheoter surface of the plate, whereby the plate ca'n be removed from'- the' mold without distortion.

ll A curved. stereotype plate' including a: plu'- rality of cir'c'jumfer'ential reenforcing ribs on the back thereof and other' reenforeing elements between said circurn-ferential ribs'. i I

12 A curved stereotype' plate' having' a back 4 reenforc'ementcomprising a plurality of ribs par.- allel to the ends thereof and' a plurality' of ribs parallel to the sides'thereof.

MARTINF W. BRUESHABER. 

